Crystalline silica catalysts

ABSTRACT

Para-xylene is selectively prepared by reacting toluene and a methylating agent in the presence of a phosphorus modified catalyst comprising a silica polymorph intermixed with an inorganic refractory oxide, said catalyst having an alkali content of less than about 1.3 milliequivalents per gram as available alkali.

RELATED APPLICATIONS

This application is a divisional of application Ser. No. 157,211, filedJune 9, 1980, now U.S. Pat. No. 4,433,187 which is a divisional ofapplication Ser. No. 12,868, filed Feb. 16, 1979, now U.S. Pat. No.4,270,017.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention resides in a process for preparing aromaticalkylating catalysts and a process for using the same.

The synthesis of alkylated aromatic hydrocarbons by reacting amethylating agent with toluene is not a new concept. Processes areavailable for producing various mixture of hydrocarbons, such as, xyleneisomers, polyalkylbenzenes, etc. The relative amount or extent to whichone or more of the above-described products is obtained is determinedand/or controlled by the type catalyst, proportions of reactants, andreactor conditions. Catalysts which have been used in the past toprepare xylenes, benzenes, etc. are those selected from acidic cogels,acid-promoted kieselguhr, and various crystalline zeolitealuminosilicates.

Zeolites are described as a three-dimensional network of structuralunits consisting of silicon-centered SiO₄ and aluminum centered AlO₄ ofa tetrahedral configuration, the tetrahedra being interconnected by amutual sharing of oxygen atoms, the structural arrangement of whichforms cavities or cells forming crystalline channels or pore openingshaving a uniform diameter characteristic of each variety or type ofcrystalline zeolite.

Silica polymorphs, such as silicalite, which are a major component inour aromatic alkylating catalysts, have a novel topological type ofcrystalline structure composed of silicate tetrahedra connected in aframework to form a three-dimensional system of intersecting channelsdefined by 10-ring members sufficiently wide enough to absorb moleculesup to 6 Å diameter. Silicalite is hydrophobic and organophilic, andselectively adsorbs organic molecules over water.

The conversion of an aromatic, for example, toluene, to a xylene, suchas para-xylene is normally a tedious and time-consuming procedure, manytimes involving a series of steps. Additionally, catalysts which possessacceptable activity generally tend to give a wide spectrum of products,for example, alkylated aromatics and hydrocarbons having a broaddistribution of carbon atoms. This not only complicates the separationand recovery of the desired product, but results in reduced yield ofsaid desired product and erosion of reactants in the production ofundesired by-products. The catalysts and process herein are particularlysuited to the selective formation of para-xylene from toluene and amethylating agent.

2. Description of the Prior Art

The reaction of toluene with a methylating agent in the presence of acatalyst to produce alkylated aromatics is appreciated and disclosed bythe prior art. However, most known processes produce an undesirablylarge mixture of alkylated aromatics in addition to the desired product.

For example, U.S. Pat. No. 4,002,698 teaches a process for methylatingtoluene to selectively produce paraxylene by contacting toluene with amethylating agent under methylation conditions in the presence of acrystalline alumino-silicate zeolite catalyst.

Another process for alkylating aromatic hydrocarbons is set forth inU.S. Pat. No. 4,025,572; particularly, the reference discloses a processfor the conversion of alcohols or ethers to olefinic and aromatichydrocarbons in the presence of a crystalline aluminosilicate zeolite.This process is described as suitable for simultaneously producingolefinic hydrocarbons and mononuclear aromatics with high selectivityfor para-xylene formation.

U.S. Pat. No. 4,061,724 relates to a crystalline silica compositionwhich is described as selective in adsorbing organic materials fromwater in either the liquid phase or vapor phase. The crystalline silicais described as suitable for removing organic compounds from wastewater.

SUMMARY OF THE INVENTION

The present invention resides in a process for preparing an aromaticalkylating catalyst and a process for using the same to alkylatearomatics, which comprises contacting a silica polymorph consisting ofcrystalline silica with an acid or an ammonium salt solution; mullingthe silica polymorph with an inorganic refractory oxide gel or sol;calcining the silica polymorph and inorganic refractory oxide for about2 hours at about 500° C.; contacting the calcined silica polymorph andinorganic refractory oxide with a phosphorus compound; and calcining theresultant catalyst for about 2 hours at about 500° C. to form a catalysthaving an alkali content of less than about 1.3 milliequivalents pergram as available alkali.

Para-xylene is selectively prepared by contacting toluene with amethylating agent under methylation conditions in the presence of acatalyst comprising a silica-polymorph in combination with an inorganicrefractory oxide, said catalyst having a silica polymorph to inorganicrefractory oxide weight ratio at from about 10:1 to about 1:10 and abulk density of from about 0.5 gm cm⁻³ to about 2.5 gm cm⁻³.

DESCRIPTION OF THE INVENTION

A catalyst and catalytic process are provided for selectively preparingpara-xylene from toluene and a methylating agent. The catalyst isprepared by sequentially extracting alkali from a silica polymorph,forming an aggregate bonded with an inorganic refractory oxide, adding aphosphorus compound and calcining the resultant catalyst.

The preferred silica polymorph herein has a topologic type oftetrahedral framework, which contains a large fraction of five-memberedrings of silica-oxygen tetrahedra. The frame-work comprises athree-dimensional system of intersecting channels which are defined asten rings of oxygen atoms extending in three directions.Precursor-organic quaternary ammonium ions which occupy the intersectingchannels, are removed by heating to yield the desired silica polymorph.The resulting void volume occupies approximately 33% of the crystalstructure, and the three-dimensional channel is wide enough to absorborganic molecules having up to about 6 Å in diameter. The silicapolymorphs, herein, degrade to a glass above about 1,300° C.

The silica polymorphs are uniquely stable, active solids which aresuitable for use as catalyst components or catalysts for hydrocarbonreactions, such as cracking, isomerization, polymerization, reforming,and alkylation.

The source of catalytic activity, of the catalysts herein, is theacidity which originates with the isolated silanol groups located in themicropores of the crystalline solid. The acidity associated with theseisolated silanol groups contrasts with the acidity of conventionalaluminosilicate catalysts prepared from cogels or zeolites. For example,the active sites of the aluminosilicates are due to negative chargesinduced on aluminum atoms by the silicate matrix. The acid sites,provided by the aluminum atoms, exceed the strength of 72% sulfuricacid; while the acid sites originating from isolated silanol groupsconsistently are weaker than 72% sulfuric acid. This moderate strength,of the silica polymorphs herein, catalyzes hydrocarbon conversion whileminimizing undesirable side reactions such as coking and lighthydrocarbon production.

Preparation of the microporous, crystalline, silica catalysts hereininclude forming a crystalline silica by hydrothermally digesting amixture of a strongly alkaline amine and amorphous silica. Next, thealkali and amine are removed by extracting with solutions of acids orammonium salts and oxidizing or thermally decomposing the ammoniacalcations. The crystalline silica is then combined with other catalyticcomponents or promoters, for example, alumina, silica, or clay bindersand hydrocarbon or hydrogen activators, such as chromium, copper,nickel, and platinum.

The sequence of adding the cataytic components can vary withoutdetrimental effect to the final catalytic activity. For example, thecrystalline silica powder may be extracted with an acid or ammonium saltsolution, washed, calcined, bonded into aggregates, contacted with aphosphorus compound and activated. Alternatively, the crystalline silicamay initially be bonded into aggregates, calcined, extracted with anacid or ammonium salt solution, contacted with a phosphorus compound,and then activated. Normally, the catalysts thus produced will have analkali content of less than about 1.3 milliequivalents per gram asavailable alkali, and a bulk density of from about 0.5 gm cm⁻³ to about2.5 gm cm⁻³, especially from about 0.5 gm cm⁻³ to about 1.5 gm cm⁻³.

The silicas produced in this invention are analogous to highly siliceousalkali silicates which form as insoluble compounds during extendedhydrothermal digestion. The amine, incorporated as a cation duringcrystallization, becomes a source of micropores when eliminated bycombustion or extraction. The surfaces of these micropores arerelatively free of hydroxyl groups. The isolated hydroxyl groups whichare present provide the moderate acidic strength of the catalyst. Itshould be noted, that the presence of a binder, such as alumina, doesnot significantly alter the characteristics of the catalysts herein.

In a preferred mode, the silica polymorph, herein is prepared by thehydrothermal crystallization of a reaction mixture comprising a silicasource, water and a strongly alkaline amine such as ethylene diamine, ora quaternary ammonium hydroxide, for example, tetrapropylammoniumhydroxide, etc. at a temperature of from about 100° C. to about 200° C.Suitable silica sources include sodium silicate, colloidal silica,silica hydrosol, silica gel, silicic acid and the like. Preparation ofthe preferred silica polymorph, herein, is described in greater detailin U.S. Pat. No. 4,061,724, the disclosure of which is incorporatedherein by reference. The preferred silica polymorph is manufactured andmarketed commercially under the tradename of Silicalite by the UnionCarbide Corporation, Tarrytown, N.Y.

Other silica polymorphs suitable for use herein include, in addition toSilicalite, UCS-3, or UCS-4 and mixtures thereof. UCS-3 and UCS-4 arenames given to silica polymorphs prepared herein. Methods of preparingthe crystalline silica designated as UCS-3 and UCS-4 and x-raydiffraction patterns thereof, are disclosed in Examples VII and VIII.These and other suitable silica polymorphs are described in greaterdetail in U.S. Pat. No. 3,941,871 and U.S. Pat. No. 4,073,865, thedisclosures of which are incorporated herein by reference.

The catalyst is prepared by initially extracting the silica polymorphwith an acid at a pH of from about 0 to about 5, preferably from about 1to about 4, for a time period of from about 10 minutes to about 10hours, especially from about 15 minutes to about 5 hours. The extractionsolution contains components selected from the group consistingessentially of nitric acid, hydrochloric acid, sulfuric acid, aceticacid, or ammonium salts such as ammonium nitrate, ammonium bisulfate andmixtures thereof. The resultant silica polymorph is collected byfiltration, washed and dried.

Next, the silica polymorph is mixed with an inorganic refractory oxidein the form of a clay, hydrogel or sol such as peptized boehmite aluminaor colloidal silica. The inorganic refractory oxides herein arepreferably selected from the group consisting of bentonite clay,boehmite alumina, silica hydrosol or colloidal silica and mixturesthereof. Other inorganic refractory oxides include alumina, silica,magnesia, beryllia or zirconia and mixtures thereof. Sufficient water ispresent to form a plastic paste. The paste is spread in a thin layer,dried, granulated to about 10/30 mesh and calcined at about 450° C.toabout 800° C. for about 10 minutes to about 10 hours. Undesirablecomponents are removed from the calcined aggregate by extraction withthe above-described acids and ammonium salts.

Normally, the silica polymorph and inorganic refractory oxide are in aweight ratio range of from about 1:10 to about 10:1, especially fromabout 1:4 to about 4:1.

It is to be noted, that the extraction step with acid or ammonium saltcan be carried out in one step, or, alternatively, can be carried out intwo or even three separate steps either before or after mixing thesilica polymorph with the inorganic refractory oxide but before additionof the phosphorus compound thereto.

The bonded, extracted silica polymorph-inorganic refractory oxidegranules are then contacted with a phosphorus containing solution forabout 5 minutes to about 2 hours at a temperature of from about 10° C.to about 60° C.; preferably from about 30 minutes to about 1 hour. Theresultant catalyst is activated by calcination for about 15 minutes toabout 4 hours at about 450° C. to about 800° C.

The amount of phosphorus incorporated with the catalyst should be fromabout 2 to about 35 percent by weight, especially from about 5 to about25 percent by weight. Representative phosphorus compounds includederivatives of groups represented by the formulae PX₃, RPX₂, R₂ PX, R₃P, X₃ PO, (XO₃) PO, (XO)₃ P, R₃ P═O, R₃ P═S, RPO₂, PPS₂, RP(O)(OX)₂,RP(S)(SX)₃, R₂ P(O)OX, R₂ P(S)SX, RP(OX)₂, RP(SX)₂, ROP(OX)₂, RSP(SX)₂,(RS)₂ PSP(SR)₂ and (RO)₂ POP(OR)₂ wherein R is alkyl or aryl and X ishydrogen, alkyl, aryl or halide. These compounds include primary,secondary or tertiary phosphines; tertiary phosphine oxides; tertiaryphosphine sulfides; primary and secondary phosphonic acids and theircorresponding sulfur derivatives; esters of phosphonic acids; thedialkyl alkyl phosphonates; alkyl dialkyl phosphonates; phosphinousacids, primary, secondary and tertiary phosphites and esters thereof;alkyl dialkylphosphinites, dialkyl alkylphosphonites their esters andsulfur derivatives.

Other suitable phosphorus-containing compounds include the phosphorushalides such as phosphorus trichloride, phosphorus tribromide,phosphorus triiocide, alkyl phosphorodichlorides, dialkylphosphorochlorides and dialkyl phosphonochloridites. Preferredphosphorus-containing compounds include phosphoric acid, phosphorusacid, and phosphate esters such as trimethylphosphate, ethylphosphite,or monophenylphosphate, etc. and mixtures thereof.

It is to be noted, that the catalysts herein are highly selective to theformation of para-xylene when contacted under methylating conditionswith toluene and a methylating agent. Aromatic-alkylating catalystssynthesized according to the procedure herein have an average poreradius of from about 30 Å to about 200 Å, preferably from about 50 Å toabout 150 Å; a surface area of from 100M² /gm to about 500M² /gm,especially from about 150M² /gm to about 350M² /gm; and a pore volume offrom about 0.33 cc/gm to about 1.0 cc/gm, preferably from about 0.5cc/gm to about 0.8 cc/gm.

In a preferred mode, the phosphorus-modified catalyst herein is preparedfrom a silica polymorph comprising silicalite in combination with aninorganic refractory oxide. Silicalite has a refractive index of 1.39and a density of 1.76. Other silica polymorphs have a refractive indexrange of from about 1.32 to about 1.45, and a density range of fromabout 1.65 to about 1.80. The catalyst is characterized by a silicapolymorph to inorganic refractory oxide weight ratio of from about 1:10to about 10:1, especially from about 1:4 to about 4:1. The finalcatalyst pore radius, surface area, pore volume and phosphorus contentare as defined above.

Methylation of toluene can effectively be carried out by contactingtoluene and a methylating agent with the above-described catalyst. Thereaction is carried out at a temperature of from about 400° C. to about600° C., preferably from about 450° C. to about 550° C., and at apressure from about 5 psia to about 250 psia, especially from about 15psia to about 100 psia. The molar ratio of toluene to methylating agentis generally from about 6:1 to about 1:2, especially from about 3:1 toabout 1:1. Suitable methylating agents include methanol, methylchloride,methylbromide, dimethyl ether, methylcarbonate, dimethylsulfide, etc.The methylation reaction is accomplished using a weight hourly spacevelocity (WHSV) of from about 1 to about 10, especially from about 2 toabout 6. Para-xylene is selectively produced in the reaction, however,it should be noted that some ortho-xylene and small amounts ofmeta-xylene may additionally be produced. Conventional methods can beused to separate the xylene isomers or the undesirable isomers may beconverted to para-xylene in an isomerization process. The methylationreaction herein can be carried out as a continuous, semi-continuous orbatch type operation, using a fixed or moving type catalyst systemutilizing conventional apparatus and techniques.

DESCRIPTION OF PREFERRED EMBODIMENTS

The following Examples serve to further illustrate and instruct oneskilled in the art the best mode of how to practice this invention andare not intended to be construed as limiting thereof.

EXAMPLE I

An aromatic alkylating catalyst was prepared by digesting silicalitepowder in an acidic 10% solution of ammonium nitrate (NH₄ NO₃) at a pHof 2.6 for about 30 minutes using 5 ml of solution per gram of silicatepowder. The solids were collected by filtration, washed, and thedigestion process was repeated for a total of two ion exchanges. Theresidual alkali content, on a calcined basis, was 0.027% sodium and0.002% potassium. Analysis indicated that the silicalite had a surfacearea of 460M² /gm. The exchanged silicalite powder (100 grams) was thenmulled with 51 grams of "Catapal S", a pure boehmite alumina powder.Sufficient 1/2 normal nitric acid was added to peptize the aluminapowder, forming a paste like mixture with the silicalite. The paste wasspread in a thin layer, dried, granulated to 10/30 mesh, and calcined 2hours at 1000° F. (537° C.).

The calcined granules were immersed in dilute phosphoric acid for 30minutes, drained, dried at 230° F. (108.9° C.), and calcined 2 hours at900° F. (477.4° C.). The resultant catalyst had a final phosphoruscontent of 14.3% (P₂ O₅) and a surface area of 283M² /gm.

EXAMPLE II

A catalyst, suitable for alkylating aromatics, was prepared by digestingsilicalite powder in an acidic 10% solution of ammonium nitrite (NH₄NO₃) at a pH of 2.6 for about 30 minutes using 5 ml of acid per gram ofsilicalite powder. The solids were collected by filtration, washed, andthe digestion process was repeated for a total of two extractions. Theresidual alkali content, on a calcined basis, was 0.027% sodium and0.002% potassium. Analysis indicated that the silicalite had a surfacearea of 460M² /gm. The exchanged silicalite powder (100 grams) was,next, mulled with 51 grams of "Catapal S", a pure boehmite aluminapowder. Sufficient 1/2 normal nitric acid was added to the silicaliteand alumina powder to form a soft paste. The paste was spread in a thinlayer, dried, granulated to 10/30 mesh, and calcined 2 hours at 1000° F.(232.4° C.). The calcined granules were digested for 16 hours at 160° F.(70.4° C.) in 3 normal ammonium bisulfate solutions (NH₄ HSO₄) using 1.4ml of ammonium bisulfate per gram of calcined granules.

Next, the calcined granules were washed three times with 1 normal aceticacid (HOAc) and with distilled water to eliminate the sulfate. Thewashed granules were dried, immersed in dilute phosphoric acid (H₃ PO₄)for 30 minutes, drained, dried at 230° F. (108.9° C.), and calcined 2hours at 900° F. (482° C.). The resultant catalyst had a finalphosphorus content of 12.9% (P₂ O₅) and a surface area of 303M² /gm.

It is to be noted that the acid-digestion of the granules in thisExample prior to phosphorus impregnation substantially increased theselectivity for forming para-xylene in a methylation reaction. However,acid-digestion prior to phosphorus impregnation is not absolutelyessential to the selective formation of para-xylene (see Example I),although, higher selective values are reported when acid-digestionoccurs in the last step of the process prior to phosphorus impregnation.

EXAMPLE III

The catalyst of Example I was evaluated for alkylation of aromatics andselectivity for para-xylene production by feeding a 2:1 molar solutionof toluene and methanol into a reactor containing said catalyst at 1000°F. (537° C.). The feed rate was 4.0 weight hourly space velocity for 3hours. Toluene conversion was 37 mole percent with 80% selectivity toxylene formation. The xylene fraction had the following distribution ofisomers:

                  TABLE 1                                                         ______________________________________                                        Compound       Wt. Percent                                                    ______________________________________                                        Para-xylene    28                                                             Meta-xylene    49                                                             Ortho-xylene   23                                                             ______________________________________                                    

EXAMPLE IV

The procedure of Example III was followed with the following exceptions:toluene and methanol were introduced into a reactor containing thecatalyst of Example I, at a weight hourly space velocity of 10 for 4.5hours. The reaction temperature was maintained at 1100° F. (593° C.)during the reaction time period. Toluene conversion was 34 mole percentwith 88% selectivity to xylene formation. The xylene fraction had thefollowing distribution of isomers.

                  TABLE 2                                                         ______________________________________                                        Compound       Wt. Percent                                                    ______________________________________                                        Para-xylene    40                                                             Meta-xylene    41                                                             Ortho-xylene   19                                                             ______________________________________                                    

The results in Examples III and IV above are to be compared withExamples V and VI to note the increase in selectivity to para-xyleneformation due to acid treating the catalyst matrix prior to phosphorusimpregnation.

EXAMPLE V

The catalyst of Example II was evaluated for aromatic alkylation andselectivity for para-xylene production by introducing a 2:1 molarsolution of toluene and methanol into a reactor, containing saidcatalyst at 1000° F. (537° C.). The feed rate was 4.0 weight hourlyspace velocity for 3 hours. Analysis indicated that toluene conversionwas 28 mole percent with 87% selectivity for xylene formation. Thexylene fraction had the following distribution of isomers.

                  TABLE 3                                                         ______________________________________                                        Compound       Wt. Percent                                                    ______________________________________                                        Para-xylene    53                                                             Meta-xylene    31                                                             Ortho-xylene   16                                                             ______________________________________                                    

EXAMPLE VI

The procedure of Example V was followed except for the followingvariations: toluene and methanol were introduced into a reactorcontaining the catalyst of Example II, at a weight hourly space velocityof 10 for 4.5 hours and a temperature of about 1100° F. (593° C.).Toluene conversion was 22 mole percent with 95% selectivity to xyleneformation. The xylene fraction had the following distribution ofisomers.

                  TABLE 4                                                         ______________________________________                                        Compound       Wt. Percent                                                    ______________________________________                                        Para-xylene    74                                                             Meta-xylene    17                                                             Ortho-xylene    9                                                             ______________________________________                                    

EXAMPLE VII

A crystalline silica suitable for use in preparing an aromaticalkylating catalyst was prepared from the following solutions:

1. Base solution, 6N NaOH

2. Silicate solution composed of:

2870 gm of commercial sodium silicate containing 8.9% Na₂ O and 28.7%SiO₂,

1670 ml of water and 9 gm of Dow-Fax 2A1 wetting agent.sup.(A)

3. Acid solution composed of:

147 ml of 36N H₂ SO₄

1730 ml of water

130 gm of NaCl

4. Organic solution composed of:

207 gm of tripropylamine

172 gm of 1-bromopropane

329 gm of methylethyl ketone

A hydrogel was formed by combining 900 ml of the above-described acidsolution with 1900 ml of the silicate solution through a mixing tee.Next, 15 ml of 6N sodium hydroxide (NaOH) was mixed with the hydrogel. A343 gm portion of the organic solution was mixed into the hydrogel. Themixture was allowed to gel and a 3400 ml portion of the hydrogel mixturewas transferred to a heated, stirred vessel pressurized with 100 psig ofnitrogen. High shear mixing was provided by two revolving paddles insidethe reaction vessel. The digestion conditions and productcharacteristics are disclosed in Table 5 below.

                  TABLE 5                                                         ______________________________________                                        Crystalline Silica   UCS-3.sup.(B)                                            Digestion Conditions                                                          Temperature, °F.                                                                            330                                                      Total Hours at Temp.  60                                                      Stirrer Speed, RPM   600                                                      Hours Stirred         60                                                      Product Qualities                                                             Nitrogen Content, wt. % N.sup.(C)                                                                  0.26                                                     Sodium Content, wt. % Na.sub.2 O.sup.(D)                                                           1.72                                                     Surface area M.sup.2 /g.sup.(D)                                                                    176                                                      ______________________________________                                         .sup.(A) DowFax 2Al45%, solution of disodium 4dodecylated                     oxydibenzenesulfonate                                                         .sup.(B) UCS3  Name given to the crystalline silica of Example VII            .sup.(C) The samples were dried at 230° F. prior to determining th     nitrogen content.                                                             .sup.(D) The samples were calcined at 800° F. prior to determining     the sodium content and surface area. The surface area was calculated from     nitrogen adsorption at 0.02 relative pressure.                           

The X-ray powder diffraction pattern of the above crystalline silica hasas its strongest lines (i.e. interplanar spacing) those disclosed inTable 6 below.

                  TABLE 6                                                         ______________________________________                                        d-Å    Relalive Intensity                                                 ______________________________________                                        18.8        .sup. VS.sup.(1)                                                  3.81       VS                                                                 3.41          S.sup.(2)                                                       3.31       VS                                                                 ______________________________________                                         .sup.(1) VS = very strong                                                     .sup.(2) S = strong                                                      

The procedure of Example II is followed to prepare an aromaticalkylating catalyst with the following exception: the crystalline silicaproduced above is substituted for the silicate powder. The catalyst thusprepared is particularly suited for selectively preparing para-xylenefrom toluene and a methylating agent.

EXAMPLE VIII

A crystalline silica suitable for use as a catalyst component in thepreparation of an aromatic alkylating catalyst was prepared according tothe procedure of Example VII with the following exceptions: Thedigestion conditions and product characteristics are set forth in Table7 below:

                  TABLE 7                                                         ______________________________________                                        Crystalline Silicas  UCS-4.sup.(A)                                            Digestion Conditions                                                          Temperature, °F.                                                                            300                                                      Total Hours at Temp.  60                                                      Stirrer Speed, RPM   600                                                      Hours Stirred         4                                                       Hours Unstirred       56                                                      Product Qualities                                                             Nitrogen Content, Wt. % N.sup.(B)                                                                  0.09                                                     Sodium Content, Wt. % Na.sub.2 O.sup.(C)                                                           0.91                                                     Surface area, M.sup.2 /gm.sup.(C)                                                                  158                                                      ______________________________________                                         .sup.(A) UCS4  Name given to the crystalline silca of Example VIII.           .sup.(B) The samples were dried at 230° F. prior to determining th     nitrogen content.                                                             .sup.(C) The samples were calcined at 800° F. prior to determining     the sodium content and surface area. The surface area was calculated from     nitrogen adsorption at 0.02 relative pressure.                           

The X-ray powder diffraction pattern of the above crystalline silica hasas its strongest lines, i.e. interplanar spacing, those disclosed inTable 8 below.

                  TABLE 8                                                         ______________________________________                                        d-Å    Relative Intensity                                                 ______________________________________                                        4.07        .sup. VS.sup.(1)                                                  4.02          S.sup.(2)                                                       3.83       VS                                                                 3.34       VS                                                                 ______________________________________                                         .sup.(1) VS = Very strong                                                     .sup.(2) S = strong                                                      

An aromatic alkylating catalyst can be prepared by substituting thecrystalline silica above for the silicalite powder in Example II. Theprepared catalyst is highly selective in preparing para-xylene fromtoluene and a methylating agent.

EXAMPLE IX

An aromatic alkylating catalyst was prepared using the method of ExampleII with the following exception: the crystalline silica of Example VIIwas substituted for silicalite and the catalyst had a phosphorus contentof 21.5% phosphorus as P₂ O₅.

The catayst thus prepared was evaluated for alkylation of toluene withmethanol and for para-xylene selectivity by feeding a 2:1 molar solutionof toluene and methanol into a reactor containing said catalyst at 1100°F. (593° C.). The feed rate was 10 weight hourly space velocity for 4.5hours. Toluene conversion was 22 mole percent with 100% selectivity toxylene formation. The xylene fraction had the following distribution ofisomers:

                  TABLE 9                                                         ______________________________________                                        Compound       Wt. Percent                                                    ______________________________________                                        Para-xylene    90                                                             Meta-xylene    6                                                              Ortho-xylene   4                                                              ______________________________________                                    

EXAMPLE X

The procedure of Example II was followed to prepare an aromaticalkylating catalyst with the following exceptions: the crystallinesilica of Example VIII was substituted for silicalite and the catalysthad a phosphorus content of 22.7% as P₂ O₅.

The catalyst was evaluated for selectivity to paraxylene formation byfeeding a 2:1 molar solution of toluene and methanol into a reactor,containing the above catalyst, at 1100° F. (593° C.). The feed rate was10 weight hourly space velocity for 4.5 hours. The converted toluene andmethanol had the following distribution of isomers:

                  TABLE 10                                                        ______________________________________                                        Compound       Wt. Percent                                                    ______________________________________                                        Para-xylene    95                                                             Meta-xylene    3                                                              Ortho-xylene   2                                                              ______________________________________                                    

Obviously, many modifications and variations of the invention, ashereinabove set forth, can be made without departing from the spirit andscope thereof, and therefore only such limitations should be imposed asare indicated in the appended claims.

I claim:
 1. A catalyst comprising a hydrogen activator and a crystallinesilica polymorph.
 2. A catalyst as defined in claim 1 where the hydrogenactivator comprises chromium.
 3. A catalyst as defined in claim 1 wherethe hydrogen activator comprises copper.
 4. A catalyst as defined inclaim 1 where the hydrogen activator comprises nickel.
 5. A catalyst asdefined in claim 1 where the hydrogen activator comprises platinum.
 6. Acatalyst as defined in claim 1 where the crystalline silica polymorphcomprises silicalite.
 7. A catalyst as defined in claim 4 where thecrystalline silica polymorph has a specific gravity at 25° C. of1.70±0.05 g/cc and a mean refractive index of 1.39±0.01 aftercalcination at 600° C. in air for 1 hour.
 8. A catalyst as defined inclaim 2 where the crystalline silica polymorph has a pore volume of 0.18cc/gram.
 9. A catalyst as defined in claim 2 where the crystallinesilica polymorph has as the six strongest d-values of its X-raydiffraction pattern d=11.1±0.2, d=10.0±0.2, d=3.85±0.07, d=3.82±0.07,d=3.76±0.05 and d=3.72±0.05.
 10. A catalyst as defined in claim 5 wherethe crystalline silica polymorph is capable of separating P-xylene fromO-xylene.
 11. A catalyst as defined in claim 4 where the crystallinesilica polymorph is capable of separating P-xylene from ethylbenzene.12. A catalyst as defined in claim 5 where the crystalline silicapolymorph is capable of separating P-xylene from m-xylene.
 13. Acatalyst comprising a hydrogen activator comprising a member selectedfrom the group consisting of chromium, copper, nickel and platinum andfurther comprising a crystalline silica polymorph.
 14. A catalyst asdefined in claim 13 where said crystalline silica polymorph has aspecific gravity at 25° C. of 170±0.05 g/cc and a mean refractive indexof 1.39±0.01.
 15. A catalyst comprising a hydrogen activator, aninorganic refractory oxide and a crystalline silica polymorph.
 16. Acatalyst as defined in claim 15 where the hydrogen activator compriseschromium.
 17. A catalyst as defined in claim 15 where the hydrogenactivator comprises copper.
 18. A catalyst as defined in claim 15 wherethe hydrogen activator comprises nickel.
 19. A catalyst as defined inclaim 15 where the hydrogen activator comprises platinum.
 20. A catalystas defined in claim 15 where said silica polymorph has an X-raydiffraction pattern with the following six strongest d-values of itsX-ray diffraction pattern: d=11.1±0.2, d=10.0±0.2, d=3.85±0.07,d=3.76±0.05 and d=3.72±0.05.
 21. A catalyst as defined in claim 15 wheresaid inorganic refractory oxide comprises a member selected from thegroup consisting of alumina, silica, magnesia, beryllia, and zirconia.22. A catalyst comprising a hydrogen activator, an inorganic refractoryoxide, and silicalite.
 23. A catalyst as defined in claim 22 where saidhydrogen activator comprises nickel and said inorganic refractory oxidecomprises a member selected from the group consisting of alumina,silica, magnesia, beryllia and zirconia.
 24. A catalyst as defined inclaim 22 where said hydrogen activator comprises platinum and saidinorganic refractory oxide comprises a member selected from the groupconsisting of alumina, silica, magnesia, beryllia and zirconia.
 25. Acatalyst as defined in claim 22 where said hydrogen activator comprisescopper and said inorganic refractory oxide comprises a member selectedfrom the group consisting of alumina, silica, magnesia, beryllia andzirconia.
 26. A catalyst as defined in claim 22 where said hydrogenactivator comprises chromium and said inorganic refractory oxidecomprises a member selected from the group consisting of alumina,silica, magnesia, beryllia and zirconia.
 27. A catalyst comprising ahydrogen activator comprising a member selected from the groupconsisting of chromium, copper, nickel and platinum, an inorganicrefractory oxide and a crystalline silica polymorph.
 28. A catalyst asdefined in claim 1 where said crystalline silica polymorph is capable ofseparating P-xylene from ethylbenzene.
 29. A catalyst comprising ahydrogen activator comprising a member selected from the groupconsisting of chromium, copper, nickel and platinum, a crystallinesilica polymorph having a pore volume of about 0.18 cc/gram, and aninorganic refractory oxide selected from the group consisting ofalumina, silica, magnesia, beryllia and zirconia.
 30. A catalystcomprising a hydrogen activator selected from the group consisting ofchromium, nickel and platinum and a crystalline silica polymorph havingas the six strongest d-values of its X-ray diffraction pattern:d=11.1±0.2, d=10.0±0.2, d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 andd=3.72±0.05.
 31. A catalyst comprising a hydrogen activator selectedfrom the group consisting of chromium, nickel and platinum, an inorganicrefractory oxide and a crystalline silica polymorph having as the sixstrongest d-values of its X-ray diffraction pattern: d=11.1±0.2,d=10.0±0.2, d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05.
 32. Acatalyst as defined in claim 31 where said refractory oxide is selectedfrom the group consisting of alumina, silica, beryllia and zirconia. 33.A catalyst comprising a hydrogen activator selected from the groupconsisting of chromium, nickel and platinum, an inorganic refractoryoxide comprising a member selected from the group consisting of alumina,silica, magnesia and zirconia, and a crystalline silica polymorphcapable of separating P-xylene from O-xylene.
 34. A catalyst comprisinga hydrogen activator comprising nickel, an inorganic refractory oxidecomprising a member selected from the group consisting of alumina,silica, magnesia and zirconia, and a crystalline silica polymorphcapable of separating P-xylene from ethylbenzene.
 35. A catalystcomprising a hydrogen activator comprising platinum, an inorganicrefractory oxide comprising a member selected from the group consistingof alumina, silica, magnesia and zirconia, and a crystalline silicapolymorph capable of separating P-xylene from m-xylene.
 36. A catalystcomprising a hydrogen activator comprising chromium, an inorganicrefractory oxide comprising a member selected from the group consistingof alumina, silica, magnesia and zirconia, and a crystalline silicapolymorph capable of separating P-xylene from O-xylene, m-xylene andethylbenzene.
 37. A catalyst comprising a hydrogen activator selectedfrom the group consisting of chromium, nickel and platinum, an inorganicrefractory oxide selected from the group consisting of alumina andsilica and mixtures thereof, and a crystalline silica polymorph havinguniform pore dimensions of about 6 Å, a specific gravity at 25° C. of1.70±0.05 g/cc, and a mean refractive index of 1.39±0.01 aftercalcination at 600° C. in air for 1 hour.
 38. A catalyst consistingessentially of a hydrogen activator, an inorganic refractory oxide and acrystalline silica polymorph having as its X-ray diffraction pattern:

    ______________________________________                                        d-A    Relative Intensity                                                                           d-A    Relative Intensity                               ______________________________________                                        11.1   100            4.35   5                                                10.02  64             4.25   7                                                9.73   16             4.08   3                                                8.99   1              4.00   3                                                8.04   0.5            3.85   59                                               7.42   1              3.82   32                                               7.06   0.5            3.74   24                                               6.68   5              3.71   27                                               6.35   9              3.64   12                                               5.98   14             3.59   0.5                                              5.70   7              3.48   3                                                5.57   8              3.44   5                                                5.36   2              3.34   11                                               5.11   2              3.30   7                                                5.01   4              3.25   3                                                4.98   5              3.17   0.5                                              4.86   0.5            3.13   0.5                                              4.60   3              3.05   5                                                4.44   0.5            2.98   10                                               ______________________________________                                    


39. The catalyst defined in claim 38 where the hydrogen activatorcomprises chromium.
 40. The catalyst defined in claim 38 where thehydrogen activator comprises copper.
 41. The catalyst defined in claim38 where the hydrogen activator comprises nickel.
 42. The catalystdefined in claim 38 where the hydrogen activator comprises platinum. 43.The catalyst defined in claim 38 where the catalyst further comprises aninorganic refractory oxide selected from the group consisting ofalumina, silica, magnesia, beryllia and zirconia and mixtures thereof.44. The catalyst defined in claim 38 where the catalyst furthercomprises an inorganic refractory oxide selected from the groupconsisting of alumina and silica and mixtures thereof.
 45. A catalystcomprising nickel, silicalite and alumina.
 46. A catalyst comprising acrystalline silica polymorph and an inorganic refractory oxide.
 47. Acatalyst as defined in claim 46 where the inorganic refractory oxide isa member selected from the group consisting of alumina, silica,magnesia, beryllia, zirconia and bentonite clay and mixtures thereof.48. A catalyst as defined in claim 46 where the crystalline silicapolymorph is capable of adsorbing organic molecules up to 6 Å indiameter.
 49. A catalyst as defined in claim 46 where the crystallinesilica polymorph has a specific gravity at 25° C. within the range offrom about 1.65 to about 1.80 g/cc and a mean refractive index withinthe range of from about 1.32 to about 1.45.
 50. A catalyst as defined inclaim 46 where the crystalline silica polymorph has as the fourstrongest d-values of its X-ray diffraction pattern d=18.8, d=3.81,d=3.41, and d=3.31.
 51. A catalyst as defined in claim 46 where thecrystalline silica polymorph has as the four strongest d-values of itsX-ray diffraction pattern d=4.07, d=4.02, d=3.83 and d=3.34.
 52. Acatalyst comprising a crystalline silica polymorph having as the sixstrongest d-values of its X-ray diffraction pattern d=11.1±0.2,d=10.0±0.2, d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05, incombination with an inorganic refractory oxide, said catalyst having abulk density within the range of from about 0.5 gm cm⁻³ to about 2.5 gmcm⁻³.
 53. A catalyst as defined in claim 52 wherein the inorganicrefractory oxide is a member selected from the group consisting ofalumina, silica, magnesia, beryllia and zirconia and mixtures thereof.54. A catalyst comprising a microporous crystalline silica and aninorganic refractory oxide.
 55. A catalyst as defined in claim 54wherein the inorganic refractory oxide is a member selected from thegroup consisting of alumina, silica, magnesia, beryllia and bentoniteclay and mixtures thereof.
 56. A catalyst consisting essentially of amicroporous crystalline silica and an inorganic refractory oxide.
 57. Acatalyst as defined in claim 56 wherein the inorganic refractory oxideis a member selected from the group consisting of alumina, silica,magnesia, beryllia, zirconia and bentonite clay and mixtures thereof.58. A catalyst comprising a crystalline silica polymorph and aninorganic refractory oxide where the crystalline silica polymorph iscapable of separating p-xylene from o-xylene.
 59. A catalyst as definedin claim 58 wherein the inorganic refractory oxide is a member selectedfrom the group consisting of alumina, silica, magnesia, zirconia andbentonite clay and mixtures thereof.
 60. A catalyst comprising acrystalline silica polymorph and an inorganic refractory oxide where thecrystalline silica polymorph and inorganic refractory oxide are in aweight ratio range of from about 1:10 to about 10:1 and said crystallinesilica polymorph is capable of separating p-xylene from ethylbenzene.61. A catalyst as defined in claim 60 wherein the inorganic refractoryoxide is a member selected from the group consisting of alumina, silica,magnesia, beryllia, zirconia and bentonite clay and mixtures thereof.62. A catalyst comprising a crystalline silica polymorph and aninorganic refractory oxide where the crystalline silica polymorph andinorganic refractory oxide are in a weight ratio range of from about 1:4to about 4:1 and said crystalline silica polymorph is capable ofseparating p-xylene from m-xylene.
 63. A catalyst as defined in claim 62where the inorganic refractory oxide is a member selected from the groupconsisting of alumina, silica, magnesia, beryllia, zirconia andbentonite clay and mixtures thereof.
 64. A catalyst comprisingsilicalite and an inorganic refractory oxide.
 65. A catalyst as definedin claim 64 where the inorganic refractory oxide is a member selectedfrom the group consisting of alumina, silica, magnesia, beryllia,zirconia and bentonite clay and mixtures thereof.
 66. A catalystcomprising silicalite and an inorganic refractory oxide selected fromthe group consisting of alumina and silica and mixtures thereof.
 67. Acatalyst comprising silicalite and alumina.
 68. A catalyst comprisingsilicalite and an inorganic refractory oxide selected from the groupconsisting of alumina, silica and magnesia and mixtures thereof whereinthe silicalite and inorganic refractory oxide are in a weight ratiorange of from about 1:10 to about 10:1.
 69. A catalyst comprising acrystalline silica polymorph and an inorganic refractory oxide where thecrystalline silica polymorph has a specific gravity at 25° C. of1.70±0.05 g/cc and a mean refractive index of 1.39±0.01 aftercalcination of 600° C. in air for 1 hour, and wherein the crystallinesilica polymorph and inorganic refractory oxide are in a weight ratiorange of from about 1:10 to about 10:1.
 70. A catalyst as defined inclaim 69 where the inorganic refractory oxide is a member selected fromthe group consisting of alumina, silica, beryllia, zirconia andbentonite clay and mixtures thereof.
 71. A catalyst as defined in claim69 where the inorganic refractory oxide is alumina.
 72. A catalystconsisting essentially of a crystalline silica polymorph and aninorganic refractory oxide where the crystalline silica polymorph has aspecific gravity at 25° C. of 1.70±0.05 g/cc and a mean refractive indexof 1.39±0.01 after calcination at 600° C. in air for 1 hour, and whereinthe crystalline silica polymorph and inorganic refractory oxide are in aweight ratio range of from about 1:10 to about 10:1.
 73. A catalyst asdefined in claim 72 where the inorganic refractory oxide is a memberselected from the group consisting of alumina, silica, beryllia,zirconia and bentonite clay and mixtures thereof.
 74. A catalyst asdefined in claim 72 where the inorganic refractory oxide is alumina. 75.A catalyst comprising a phosphorus compound and a crystalline silicapolymorph.
 76. A catalyst as defined in claim 75 wherein said catalystfurther contains an inorganic refractory oxide.
 77. A catalyst asdefined in claim 75 wherein said catalyst further comprises alumina. 78.A catalyst as defined in claim 75 wherein said refractory oxide isselected from the group consisting of alumina, silica, magnesia,beryllia, zirconia, and bentonite clay.
 79. A catalyst as defined inclaim 75 wherein said silica polymorph is silicalite.
 80. A catalyst asdefined in claim 76 wherein said silica polymorph has a specific gravityat 25° C. of 1.70±0.05 g/cc and a mean refractive index of 1.39±0.01.81. A catalyst as defined in claim 77 wherein said crystalline silicapolymorph has as the six strongest d-values of its X-ray diffractionpattern d=11.1±0.2, d=10.0±0.2, d=3.85±0.07, d=3.82±0.07, d=3.76±0.05and d=3.72±0.05.
 82. A catalyst as defined in claim 78 wherein saidcrystalline silica polymorph has as the six strongest d-values of itsX-ray diffraction pattern d=11.1±0.2, d=10.0±0.2, d=3.85±0.07,d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05.
 83. A catalyst as defined inclaim 76 wherein said catalyst has a surface area from 100 M² /gm toabout 500 M² /gm.
 84. A catalyst as defined in claim 83 wherein saidsilica polymorph has a pore volume of 0.18 cc/gram.
 85. A catalyst asdefined in claim 76 wherein the crystalline silica polymorph andinorganic refractory oxide are in a weight ratio range of from about1:10 to about 10:1.
 86. A catalyst as defined in claim 85 wherein saidsilica polymorph is silicalite and said refractory oxide is selectedfrom the group consisting of alumina, silica, zirconia, magnesia,beryllia, and bentonite clay.
 87. A catalyst as defined in claim 85wherein said crystalline silica polymorph has as the six strongestd-values of its X-ray diffraction pattern d=11.1±0.2, d=10.0±0.2,d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05.
 88. A catalyst asdefined in claim 87 wherein said refractory oxide is alumina.
 89. Acatalyst as defined in claim 75 wherein said phosphorus compound is aphosphorus oxide.
 90. A catalyst as defined in claim 76 wherein saidphosphorus compound is a phosphorus oxide.
 91. A catalyst as defined inclaim 80 wherein said phosphorus compound is a phosphorus oxide.
 92. Acatalyst as defined in claim 81 wherein said phosphorus compound is aphosphorus oxide.
 93. A catalyst as defined in claim 86 wherein saidphosphorus compound is a phosphorus oxide.
 94. A catalyst as defined inclaim 88 wherein said phosphorus compound is a phosphorus oxide.
 95. Acatalyst comprising a microporous crystalline silica and a promotercontaining a component selected from the group consisting of platinum,phosphorus, chromium, nickel, and copper.
 96. A catalyst as defined inclaim 95 wherein said catalyst further comprises an inorganic refractoryoxide.
 97. A catalyst as defined in claim 96 wherein said refractoryoxide comprises alumina.
 98. A catalyst as defined in claim 96 whereinsaid refractory oxide comprises silica.
 99. A catalyst as defined inclaim 95 wherein said crystalline silica has as the six strongestd-values of its X-ray diffraction pattern d=11.1±0.2, d=10.0±0.2,d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05.
 100. A catalystas defined in claim 95 wherein said crystalline silica has as the fourstrongest d-values of its X-ray diffraction pattern d=18.8, d=3.81,d=3.41, and d=3.31.
 101. A catalyst as defined in claim 95 wherein saidcrystalline silica has as the four strongest d-values of its X-raydiffraction pattern d=4.07, d=4.02, d=3.83, and d=3.34.
 102. A catalystas defined in claim 96 wherein said crystalline silica has as the sixstrongest d-values of its X-ray diffraction pattern d=11.1±0.2,d=10.0±0.2, d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05. 103.A catalyst as defined in claim 97 wherein said crystalline silica has asthe six strongest d-values of its X-ray diffraction pattern d=11.1±0.2,d=10.0±0.2, d=3.85±0.07, d=3.82±0.07, d=3.76±0.05 and d=3.72±0.05.